Category: Teaching

Enzymes don’t necessarily increase the rate at which products are formed

An enzyme increases the rate of product formation What happens if you add the enzyme malate dehydrogenase to a mixture of of its substrates NAD and malate (both at 1 mM for the sake of argument)? A brief look on BRENDA indicates that the reaction malate dehydrogenase catalyses is: malate + NAD → oxaloacetate + …

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The product of succinate dehydrogenase is ubiquinol not reduced flavin

Succinate dehydrogenase [CC-BY-SA-3.0 Steve Cook, based on PDB 1NEK: Yankovskaya, V., Horsefield, R., Tornroth, S., Luna-Chavez, C., Miyoshi, H., Leger, C., Byrne, B., Cecchini, G., Iwata, S. (2003) Architecture of succinate dehydrogenase and reactive oxygen species generation. Science 299:700-704 doi: 10.1126/science.1079605]

Succinate dehydrogenase (SDH) produces reduced flavin (FADH2) as a product This misconception is so widespread, even the exam boards get it wrong. Page 41 of the Edexcel GCE specification for A-level biology (2008 onwards) states that students should be able to… Describe the role of the Krebs cycle in the complete oxidation of glucose and formation …

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Misconceptions in life sciences

Ball in flight misconceptions [copyright free]

Last month, I was involved in teaching on a life science communication course, some of the results of which you can see on Wikipedia. One of our guest speakers was Alom Shaha, who demonstrated the misconceptions students have about e.g. the forces acting on a ball in flight: A typical response demonstrates some common misconceptions, …

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Educational RCTs

Practice makes perfect [CC-BY-SA-3.0 Steve Cook]

Around a decade ago I did a PGCE. Part of that PGCE involved a small-scale investigative study, from which I learnt a great deal about educational research, but not – I suspect – any of the intended learning outcomes. I was teaching a year-7 class, whose graphing skills needed improvement. Students would often forget to …

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Illuminating error

pGLO contamination [CC-BY-SA-3.0 Steve Cook]

Yesterday’s first-year biology practical involved forcing the laboratory work-horse bacterium Escherichia coli to take up a circular piece of DNA called pGLO. pGLO contains a few genes, but the most interesting of these DNA sequences encodes a protein from a jellyfish. This protein fluoresces green under UV light, and goes by the thoroughly unimaginative name of green fluorescent …

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Vorticella micrograph [CC-BY-SA-3.0 Steve Cook]

It’s nice to find out that – old and jaded as I am – biology can still delight me. Earlier this week, I covered a first-year practical teaching microscopy skills to first-years, through the medium of pond water. As well as the usual desmids, rotifers, Daphnia and nematodes, one lucky student found a little clump …

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Educated guesswork

Enterobacter W1 [CC-BY-SA-3.0 Steve Cook]; cylindrical cells about a micron long

Someone recently asked me, “How many cells are there in the human body?” I have quite a lot of correspondence of this kind, just to be clear. I have to confess my first thought was “Not a bloody clue”. My second thought was “I bet the Internet knows”; but my third was “The Internet is full of …

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Community payback for undergrads

Brocchinia reducta, Hampton Court flower show 2003 [CC-BY-SA-3.0 Steve Cook]

Two acquaintances of mine, both teachers of one kind or another, tell me that they no longer feel comfortable steering students away from Wikipedia, because they can no longer maintain the prim pretence that they themselves aren’t consulting it on a daily basis. I’ve long appreciated Wikipedia for its convenience; and been amused by its unforgivable mis-prioritisation. On the other hand, I’ve been …

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